1. Field of Invention
This invention relates in general, to firearms of the revolver type having interchangeable barrels and ammunition cylinders and in particular, to such firearms wherein the interchangeable barrels and cylinders provide a change in the caliber of ammunition to be used with the firearm.
2. The Prior Art
Firearms having interchangeable critical parts such as barrels and ammunition discharge chambers are well known. Such firearms include revolver type weapons in which the ammunition cylinder has a multiplicity of chambers therein and is interchangeable along with the barrel of the weapon. This particular variation has even been used to provide for a change in the caliber of ammunition to be used with the weapon by the matching of interchangeable ammunition cylinders with interchangeable barrels corresponding to the same caliber of ammunition.
In particular, U.S. Pat. No. 3,280,495 discloses a revolver type firearm having a frame for mounting interchangeable ammunition cylinders and barrels. The barrels thereof include a threaded end portion for engagement with the frame and an extension therefrom for reaching past the weapon frame and interfering with ammunition cylinders corresponding to calibers of ammunition larger than that associated with the barrel. This firearm is intended to prevent the use of cylinders for larger caliber ammunition than that for which the mounted barrel is intended. The firearm disclosed includes a shroud which is held to the front of the frame and which surrounds the barrel. The barrel has a nut like structure located at the end opposite the threaded portion which extends beyond the shroud and is used for applying torque for installing and removing the barrel from the frame. Unfortunately, it is still relatively easy, with the firearm disclosed in this patent, to combine an ammunition cylinder of a larger caliber ammunition with a barrel corresponding to a smaller caliber ammunition. The reason for this is that the barrel disclosed in that patent may be installed in the frame without being fully threadedly engaged therein and thus the longitudinal extension at the rear of such a defectively installed barrel would not be operative to interfere with ammunition cylinders for ammunition of larger calibers. The weapon disclosed is such that the full threaded engagement of the barrel or lack thereof may not be readily noticeable upon examination of the weapon.
Another firearm having interchangeable barrels allowing for the use of different caliber ammunition therein is disclosed in U.S. Pat. No. 1,357,393. That patent discloses a pistol having a frame and barrel. The frame includes a firing mechanism but does not include means for mounting a revolver type ammunition cylinder. The bottom of the barrel includes a rib which is intended for insertion in a complementary slot located in the frame. The barrel is secured to the frame by a screw passing through the frame and engaging a portion of the rib. Thus, the only interchangeable part on the weapon is the barrel and the patent does not deal with the problems encountered by having to interchange both the barrel and the ammunition cylinder.
Another means for interchanging barrels on a firearm is disclosed in U.S. Pat. No. 3,877,167. That patent discloses a gun barrel having a locking bushing securely threaded onto its rearward end. The locking bushing is receivable in a breech casing and includes a slot engageable by a pin fixedly located within the breech casing to fix the rotational position of the barrel therein. The barrel is held in the casing by a second bushing rotatable around the barrel and located thereon above the first bushing. The second bushing threadedly engages the breech casing and abuts against the first bushing to press the gun barrel and first bushing into the casing. Thus, this patent does not deal with those problems encountered with a firearm having both interchangeable barrels and ammunition cylinders.
Another means for removably mounting a barrel in a receiver assembly is disclosed in U.S. Pat. No. 3,731,418. In that patent, the receiver assembly is longitudinally slit to permit a receiver flange located thereon to be circumferentially constricted into clamping engagement with the barrel. The patent does not deal with the difficulties encountered with firearms having both interchangeable barrels and ammunition cylinders.
Another method for removably attaching a gun barrel to a receiver therefor is disclosed in U.S. Pat. No. 529,455. The rear portion of the barrel is threaded to receive several bands, one of which is discontinuously threaded so as to thereby have an equal number of threaded and nonthreaded portions evenly distributed around the circumference of the band. The receiver in turn includes a similarly discontinuous thread engageable with the discontinuously threaded band. Engagement is had between the discontinuous threads by inserting them when a threaded portion of one thread is aligned with a blank portion of the other thread. After the threads are so inserted to their fullest extent, the band is rotated less than one full revolution to engage the complementary threaded portions. Thus arranged, the barrel can be easily assembled to the receiver or disconnected therefrom by the described partial rotation of the discontinuously threaded band. The weapon described does not include a revolver type ammunition cylinder or means for installing barrels having different calibers.
Another mechanism for removably attaching a gun barrel to a receiver is disclosed in U.S. Pat. No. 534,691. In this patent the rearward end of the gun barrel includes a thread located on the upper portion thereof. The receiver includes a hole for receiving the rearward end of the gun barrel. The hole includes a thread, complementary to the thread on the rearward end of the barrel, engageable therewith and located on the upper side of the hole. The hole is oval in shape and includes an intersecting cylindrical bore at the lower end thereof. To attach the barrel to the receiver, the barrel is inserted into the hole at the lower end thereof, thus preventing engagement of the threads located on the barrel and on the inside of the hole. After the barrel is fully inserted, a tapered bolt is located within the intersection cylindrical bore and secured by rotation. The taper of the bolt forces the gun barrel upward in the receiver hole, thus causing the complementary threads to engage securing the gun barrel in the receiver. Thus, this patent does not disclose a firearm having a revolvable ammunition cylinder and does not discuss such firearms having both interchangeable barrels and ammunition cylinders.